1. Field of the Invention
The present invention relates to a method of driving a plasma display panel and a plasma display apparatus, and more particularly, to improvements in an interlace-type plasma display panel and a technique of driving of a plasma display panel in an interlaced fashion.
2. Description of the Related Art
A technique of driving, in an interlaced fashion, a plasma display panel (hereinafter referred to as a PDP) is disclosed, for example, in Japanese Unexamined Patent Application Publication No. 9-160525. In this technique disclosed in the patent cited above, X electrodes (display electrodes) and Y electrodes (scanning electrodes) are formed on a PDP such that an equal gap is formed between any two adjacent electrodes and such that an electric discharge can occur in any discharge gap. Using the PDP constructed in such a manner, an image is displayed in an interlaced fashion by generating discharges alternately in odd electrode gaps (discharge gaps) and even electrode gaps (discharge gaps). This technique allows achievement of greater resolution and higher brightness in a displayed image than can be achieved in other conventional PDPs.
FIGS. 1 and 2 show the structure of the interlace-type PDP panel based on the technique cited above. In FIGS. 1 and 2, X1, X2, and X3 denote display electrodes 11, Y1, Y2, and Y3 denote scanning electrodes 12, and A1 to A6 denote address electrodes 21. Each display electrode 11 is formed of a transparent electrode 11i and a bus electrode 11b, and each scanning electrode 12 is formed of a transparent electrode 12i and a bus electrode 12b. L1 to L5 denote discharge gaps, each of which forms a display line. Furthermore, barrier ribs 25 are formed so as to partition a surface discharge between each display electrode 11 and a corresponding adjacent scanning electrode 12 into a plurality surface discharges (that is, into a plurality of cells), and fluorescent layers 26R, 26G, or 26B for emitting red, green, or blue light are formed between two adjacent barrier ribs 25.
FIGS. 3A and 3B shows waveforms of driving signals used to drive the above-described PDP in a display period.
During the display period in which a display discharge is generated, as shown in FIGS. 3A and 3B, the phase of the driving pulses applied to the electrodes becomes opposite between the odd X electrodes Xodd and the odd Y electrodes Yodd and also between the even X electrodes Xeven and the even Y electrodes Yeven in odd fields (also called odd frames). Therefore, discharges occur in the odd display lines Lodd (L1, L3, and L5, in FIG. 1), and thus odd display lines serve as display lines in the odd fields. On the other hand, in even fields (also called even frames), the phase of the driving pulses becomes opposite between Xodd and Yeven and also between Xeven and Yodd. Thus, discharges occur in even display lines Leven (L3 and L4 in FIG. 1), and even display lines serve as display lines in the even fields.
By changing the driving waveforms in the above-described manner between the odd field (odd frames) and the even fields (even frames), all electrode gaps equally formed between the display electrodes 11 and the scanning electrodes 12 on the PDP can be used as display lines. This makes it possible for the PDP to display an image with high resolution and high brightness.
In the conventional interlace-type PDP (FIGS. 1 and 2), as described above, all electrode gaps are formed so as to have an equal gap distance, and all electrode gaps can be used as display lines (discharge gaps). If one of electrode gaps is used as a discharge gap (in which a display discharge occurs) in either an odd field (odd frame) or an even field (even frame), this electrode gap must be a non-discharge gap (in which no display discharge occurs) in the other field (frame).
The gap distance of each electrode gap is set to a rather small value so that the electrode gaps can function well when they are used as discharge gaps in the odd field (odd frame) or even field (even frame). However, when electrode gaps are used as non-discharge gaps in the other type of field (frame), that is, when they are used as gaps for isolating cells, the gap distance determined in the above-described manner is not large enough for use as the non-discharge gaps.
In the above-described technique disclosed in Japanese Unexamined Patent Application Publication No. 9-160525, to solve the above problem, voltages are applied to the electrodes so that the phase of voltage becomes equal between the adjacent electrodes between which there is a non-discharge gap, thereby reducing the voltage across the non-discharge gap to a small level (or a voltage equal to 0). However, in this conventional technique of driving the interlace-type PDP, there is a limitation on a further improvement in the operation margin.
Thus, there is a need to improve the structure of the PDP, the method of driving the PDP, and the waveform used in the driving of the PDP so as to have a greater operating margin.